Definition: You are given a question on virology. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: The highest risk of HIV infection among drug users in the U.S. is in:
(A)The east coast (B)The central United States (Kansas, Missouri etc.) (C)Southern California (D)The Pacific Northwest (Washington, Oregon, Idaho)

A